Technology for Granulating Coke Breeze by Centrifugal Rolling Type Pelletizer and Effect of Granulated Coke Breeze on Sintering Operation

Abstract

Coke breeze was granulated by a centrifugal rolling type pelletizer which was operated at a Froude number (Fr) that is more than 10² times that for the conventional drum mixer. The effects of the coke breeze granulated by this new technology on the sintering opetation, the granulation of raw mix for sintering, and the quality of sinter were quantitatively studied through sintering pot test and plant test at Nagoya No. 2 Sintering Plant. As a result, the following findings were obtained:
(1) In the coke breeze granulation test, the centrifugal rolling type pelletizer could not only granulate fine coke breeze but also cause ultra-fine coke particles to penetrate into coarser particles, while preventing the granulated particles from becoming excessively coarse.
(2) In the sintering pot test and sintering plant test, it was clarified that granulated coke breeze became the nuclei of quasi-particles of the raw mix for sintering and then promoted the granulation of other raw materials in the iron ore sintering process.
(3) It was confirmed that this new technology could decrease NO_x emissions by reducing the ratio of fine particles in coke breeze. NO_x emissions could be further reduced by the addition of quick lime. It was also clarified that the reducibility of sinter was improved.